Light tight photographic film cartridge



March7, 1933. J G,JONES 1,900,879

LIGHT TIGHT PHOTOGRAPHIC FILM CARTRIDGE Filed July 27, 1929 JOhn/ G. James 1" Y B g I r A TTORNEYS.

INVENTOR:

Patented Mar. 7, 1933 UNITED STATES JOHN 3' ONES, OF ROCHESTER, NEW YORK,

ASSIGNOR EASTMAN KODAK COMPANY,

OF ROCHESTER, NEW YOBK,-A CORPORATION OI NEW YORK LIGHT TIGHT PHOTOGRAPHIC FILM CARTRIDGE Application filed July 27, 1929. Serial 1W0. 381,589.

This invention relates to photographic film cartridges in which strips of photographic film and a light protective covering are wound in oonvolutions upon a flanged spool. One object of my invention is to provide a protective covering for-the film in which the longitudinal edges which normally-contact with the film spool flanges are of greater length than the medial portion of the strip. Another object of my invention is to provide a film backing paper or protective covering having the edges stretched into a curved shape which both facilitates spooling the film and backing paper upon the flanged spool and reduces the possibility of light entering betweenthe spool flanges and the backing paper. Another object of my invention is to provide a protective covering for the film which is easy to make and which can be readily kept within the desired limits of size. Still another object of my invention is to provide a protective covering for photographic film in which the edges are stretched to such an extent that .the protective covering will lie in a smooth curve against the spool flanges while the medial portion of the strip lies flat against the supporting convolutions of film and paper. Other objects will appear from the following specification, the novel features being particularly pointed out in the claims at the end thereof.

A great deal of work has been done on the reduction of light fog by altering the protective covering for the film backing paper. In Patents Numbers 1,454,812-3-l5-6-7, all issued May 8, 1923 to John G. Jones "for photographic film cartridge, there are shown a number of methods 01 preventing light fog. These patents all. relate to film backing papers in which the thickness of the protective covering is difierent between different areas of the covering. In some cases the edges of the film backing paper is made thinner than the medial portions thereof and in other cases the film backing paper edges are folded longitudinally of the strip.

This invention differs from the protective coverings shown in the above patents in that while the thickness of the film backing paper may be slightly reduced by the stretching reference cperation there is not a very material change in the thickness of the backing paper and since it does not require a' definite thinning of portions of the protective covering the dilficulty of reducing the paper thickness in places is not present. a y

Coming now to the drawing wherein like characters denote like parts throughout:

Fig. 1 is a perspective view of the partial- 1y unrolled film cartridge constructed in accordance and embodying a preferred form of my invention;

Fig. 2 is a plan view of an unrolled film cartridge equipped with backing paper having stretched edges, the scale being broken;

Fig. 3 is a fragmentar plan view of a section of motion picture strip provided with stretched edges;

Fig. 4 is a fragmentary end view on an enlarged scale or: a film protective covering partially wound on a film spool; and

Fig. 5 is a greatly enlarged perspective view of a section of the stretched backing paper before being slit.

The ordinary photographic film cartridge consists of a strip of film 1 which is protected by backing paper 2 to which the film may be attached by means of a suitable pester 3, the convolution of film and backing paper being wound on a spool having a core 4, and flanges 5.

In accordance with my invention the backing paper 2 is provided with a stretched edge 6. T. prefer to stretch both edges of the film backing paper.

Because it is practically impossible to Sl'lOW in a drawing the way such a stretched backing paper actually looks, I have labelled in the drawing the edge as being stretched edges, and have shown on a greatly enlarged scale a series of shade lines which are intended to indicate the curvature of the edge of the paper.

, When the stretched wound on a film spool in a smooth curve as edge backing paper is the stretched edge lies indicated at 7, Fig. 1 against the inside 8 of the film spool. However, when the protective covering is drawn taut away from the spool the stretched edge 1111 having a leader reeentawa 'a ranceasindicated .8't91 flFi.1. V pp, l

. The

sheets by -sion and at the desired ,andfromthefilm It sh d be understood, however, that the magnitude of the stretched portion of the protective covering is so slight that by casuallyl at a film cartridge nipped with this type backi paper it is hat to tell whether or not the ge is stretched. Close inspection will indicate, however, that the stretched edge turns up very slightly against the film spool flanges and when drawn out there is a slight wavy a pearance due to the length of the edges of t e backingupa 1 being greater (because of the stretc 'ng than e main ortion of the sheet.

By hol ing the paper stri with one edge.

u and sighting along the go the stretched ge is very noticeable although when lying flat the stretched edge is not nearly so apparent. In order to give a little idea of the size of the stretched edge reference may be had to Fig. 5 wherein the dimensions A and B indicate a preferred dimension for the stretching operation.

A, which is theradius of curvature, may be a proximately .5" and B, which 1s the heiglit of the stretched portion above the plane surface of the bacln'ng pa r sheet 2 may be .020". I preferably cut t e film protective pa r .010" wider than the distance between t lus or minus .004. It is to be unders t at these dimensions are purely by way of illustration and that successful stretched edge backin paper may be made by widely varyin the imensions of the ridge R which is stretc ed into the sheet.

pa r is normally stretched in wide wing it tightly over rollers having a plurality of ridges of the desired dimenacing thereon. By drawing the paper tighffy around a roller so shaped the ridges R are stretched into the sheet while the paper is in a curved position. This causes the stretched edges of the sheet to lie smooth and snu against the film espool flanges when the bac paper is 0011 on the core. 1

After stretching the wide sheet of paper so that a plurality of small ridtges extend through the length of the sheet ese ridges may be slit along the line S, Fig. 5 so that each edge of the film backing aper is provided with an arcuate curved e ge 6. Of course, the paper may be slightly thinned by the stretc operation but since the paper is changed its normal shape b stretching and not by abrading or cutting t ere is not a great reduction in the thickness along the edges and there is an upwardly curved are which permits the papelisto wind smoothly to spoo For instance as indicated in Fig. 4 the stretched edge 6 is shown on a considerably xaggerated scale. It will benoticed that the e film spool flanges. These may normally var slightly wrinkled edge indicated by the shade lines at 9 gradually smooths out as it approaches the curvature of the convolution C of film and pa film core 4. T e fact that the backing paper 2 will have slightly wrinkled edges w en the V paper is drawn out behind the film in a camera for exposure is immaterial because this wrinkling is very slight andexists only at the extreme edges of the backing paper so that the usual springs and film tension pads in photographic cameras can function exactly asthey always do. I

For motion picture film and particularly for the amateur size of motion picture film which is coiled in convolutions on a film spool with a leader and sometimes a tail strip of' protective covering, the stretched edge backing paper is also useful. ma carry perforations 12 and may be attac ed at 13 to a protective coverin 14 having a rtures 15, the edges 16' w ich are shade are stretched edges although the magnitude of the stretching indicated m'the drawing is greatly magnified since the actual stretche gortion is of very small imension. As in t e case of the roll film cartridge shown and described in Fig. 1 stretched edge 16 wrinkles slightly when drawn out flat as shown in Fig. 3 but when coiled upon a suitable film spool these wrinkles flatten out to form a curved surface which lies snu 1y ainst the flanges of the film spools an; is e ective to prevent light from leaking down between the convolutlons of paper and film and the film spool flanges.

In the specification and claims the words smooth 'or smoothly are intended to cover the stretched ed es of my backing paper either in a flat, slightly wavy condition or in the dsiilnootlh gplilildgtitign which is caused b win gt e ac aperuponas In both cases the stretcl edges are sm th in that the are free from any corrugations or permanen y formed co rations as might be formed by embossing ro ers.

Having thus described my invention, what claim as new and desire to secure by Letters Pater}: is:

1. protective cover for hoto hic light sensitive film com l i sing a strip d f rotect1ve paper having t e longitudinal edges thereof smoothl stretched thereby having a slightly wavy e ge when unrolled.

2. A protective covering for photographically light sensitive film comprising a strip of protective paper having the longitudinal edges thereof smoothly stretched into an arcuate shape in cross section thereb having a slightly wavy edge when unroll 3. A protective covering for photographically light sensitive film comprising a strip of paper adapted to be interwound on a spool with the film, the longitudinal edges of said strip being smoothly stretched whereby said r which are coiled about the In Fig. 3 the film 11 III 35 day of July 1929.

may lie in a smooth even curve when 00 .d upon a spool, and may lie in a slightly wavyboonldition wlifln tililfigmpdl itsiunrolle'dr.

4. p otogra'p 'c cartri ge comprising coiled strips. f sensitized material, and oonvolutions of protective material mterwolmd therewith, the edges of the protective material being smoothl. stretched whereby the edges are of geater length than the m medial portion of e strip thereby causing said film protective material to have a slightly wivy edge when unrolled. 5. As an article of manufacture comfiris ing a spool with'end flanges, ban s of 'ghti 1 15 sensitive film and of protective aper wound thereon, the protective pager and having smoothly stretched edges 0. apted to contact and lie smoothly against the flanges of the spool and adapted when unrolled to have a a0 shghfly y e I 6. A protective covering for photographic light-sensitive film comprising a protective paper having the edges thereof stretched ongitudinally of the strip and presenting a 25 smooth curved surface. I 7. A photographic film cartridge compris- V ing coiled strips of sensitized material, and eonvolutions of protective material terwound therewith, the edges of said protective material being smoothly stretched into a greater length than the remainder of the protective paper thereby having a slightly wavy edge when unrolled. F V Signed at Rochester,New York this 22nd JOHN ,G. JONES. 

